Polar code encoding method and encoding apparatus

ABSTRACT

The present invention discloses a polar code encoding method and encoding apparatus. The method includes: mapping M reserved bits of a broadcast signaling respectively to M low-reliability information bits in K information bits of a polar code, and mapping remaining bits of the broadcast signaling to remaining information bits of the K information bits, to obtain bits after mapping, where M&lt;K, and both M and K are positive integers; and performing polar code encoding on the bits after mapping, to obtain coded bits after encoding. Embodiments of the present invention can improve broadcast signaling transmission reliability.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2014/094475, filed on Dec. 22, 2014, the disclosure of which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments of the present invention relate to the field of encoding anddecoding, and more specifically, to a polar code encoding method andencoding apparatus.

BACKGROUND

In a communications system, channel encoding is usually performed toimprove data transmission reliability and ensure communication quality.A polar code is an encoding manner that can achieve a Shannon capacityand has low coding-decoding complexity. The polar code is a linear blockcode, including one or more information bits and one or more frozenbits. A generator matrix of the polar code is G_(N), and an encodingprocess of the polar code is X₁ ^(N)=u₁ ^(N)G_(N), where u₁ ^(N)={u₁,u₂, . . . , u_(N)} is a binary row vector with a length of N.

SUMMARY

When a polar code is used for channel encoding of a physical broadcastchannel (PBCH), broadcast channel transmission reliability can befurther improved.

Embodiments of the present invention provide a polar code encodingmethod and encoding apparatus, so as to improve broadcast signalingtransmission reliability.

According to a first aspect, an embodiment of the present inventionprovides a polar code encoding method, including:

-   -   mapping M reserved bits of a broadcast signaling respectively to        M low-reliability information bits in K information bits of a        polar code, and mapping remaining bits of the broadcast        signaling to remaining information bits of the K information        bits, to obtain bits after mapping, where M<K, and both M and K        are positive integers; and    -   performing polar code encoding on the bits after mapping, to        obtain coded bits after encoding.

With reference to the first aspect, in a first implementation manner ofthe first aspect, the M low-reliability information bits include Minformation bits with reliability lower than a preset threshold, or theM low-reliability information bits include M information bits withlowest reliability in the K information bits.

With reference to the first aspect and the foregoing implementationmanner of the first aspect, in a second implementation manner of thefirst aspect, before the mapping M reserved bits of a broadcastsignaling respectively to M low-reliability information bits in Kinformation bits of a polar code, the encoding method further includes:

-   -   sorting the K information bits according to reliability of the K        information bits.

With reference to the first aspect and the foregoing implementationmanners of the first aspect, in a third implementation manner of thefirst aspect, the reliability of one of the K information bits isdetermined according to a bit capacity, a Bhattacharyya parameter suchas a Bhattacharyya distance, or an error probability.

With reference to the first aspect and the foregoing implementationmanners of the first aspect, in a fourth implementation manner of thefirst aspect, after the performing polar code encoding on the bits aftermapping, to obtain coded bits after encoding, the encoding methodfurther includes:

-   -   performing sorted congruential interleaving on the coded bits        after encoding, to obtain coded bits after interleaving; and    -   inputting, according to a preset value E, the first E bits of        the coded bits after interleaving into a cyclic buffer; or    -   performing order-reversing processing on the coded bits after        interleaving, and inputting, according to a preset value E, the        first E bits of the coded bits after order-reversing processing        into a cyclic buffer.

With reference to the first aspect and the foregoing implementationmanners of the first aspect, in a fifth implementation manner of thefirst aspect, the performing sorted congruential interleaving on thecoded bits after encoding, to obtain coded bits after interleavingincludes:

-   -   obtaining a congruential sequence according to a length of the        coded bits after encoding;    -   performing sorting processing on the congruential sequence        according to a preset rule, to obtain a reference sequence;    -   determining a mapping function according to the congruential        sequence and the reference sequence; and    -   interleaving the coded bits after encoding according to the        mapping function, to obtain the coded bits after interleaving.

With reference to the first aspect and the foregoing implementationmanners of the first aspect, in a sixth implementation manner of thefirst aspect, the obtaining a congruential sequence according to alength of the coded bits after encoding includes:

-   -   determining the congruential sequence according to the following        formula:

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0, 1, . . . , (N−2),

-   -   where N is the length of the coded bits of the polar code after        encoding, x₀, a, c, and m are particular parameters, and x(0),        x(1), . . . , x(N−1) is the congruential sequence.

According to a second aspect, an embodiment of the present inventionprovides an encoding apparatus, including:

-   -   a mapping unit, configured to: map M reserved bits of a        broadcast signaling respectively to M low-reliability        information bits in K information bits of a polar code, and map        remaining bits of the broadcast signaling to remaining        information bits of the K information bits, to obtain bits after        mapping, where M<K, and both M and K are positive integers; and    -   an encoding unit, configured to perform polar code encoding on        the bits after mapping, to obtain coded bits after encoding.

With reference to the second aspect, in a first implementation manner ofthe second aspect, the M low-reliability information bits include Minformation bits with reliability lower than a preset threshold, or theM low-reliability information bits include M information bits withlowest reliability in the K information bits.

With reference to the second aspect and the foregoing implementationmanner of the second aspect, in a second implementation manner of thesecond aspect, the encoding apparatus further includes a sorting unit,configured to sort the K information bits according to reliability ofthe K information bits.

With reference to the second aspect and the foregoing implementationmanners of the second aspect, in a third implementation manner of thesecond aspect, the reliability of one of the K information bits isdetermined according to a bit capacity, a Bhattacharyya parameter suchas a Bhattacharyya distance, or an error probability.

With reference to the second aspect and the foregoing implementationmanners of the second aspect, in a fourth implementation manner of thesecond aspect, the encoding apparatus further includes an interleavingunit and a capturing unit, where

-   -   the interleaving unit is configured to perform sorted        congruential interleaving on the coded bits after encoding, to        obtain coded bits after interleaving; and    -   the capturing unit is configured to input, according to a preset        value E, the first E bits of the coded bits after interleaving        into a cyclic buffer; or    -   configured to: perform order-reversing processing on the coded        bits after interleaving, and input, according to a preset value        E, the first E bits of the coded bits after order-reversing        processing into a cyclic buffer.

With reference to the second aspect and the foregoing implementationmanners of the second aspect, in a fifth implementation manner of thesecond aspect, the interleaving unit is configured to:

-   -   obtain a congruential sequence according to a length of the        coded bits after encoding;    -   perform sorting processing on the congruential sequence        according to a preset rule, to obtain a reference sequence;    -   determine a mapping function according to the congruential        sequence and the reference sequence; and    -   interleave the coded bits after encoding according to the        mapping function, to obtain the coded bits after interleaving.

With reference to the second aspect and the foregoing implementationmanners of the second aspect, in a sixth implementation manner of thesecond aspect, the interleaving unit is configured to determine thecongruential sequence according to the following formula:

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0,1, . . . , (N−2),

-   -   where N is the length of the coded bits of the polar code after        encoding, x₀, a, c, and m are particular parameters, and x(0),        x(1), . . . , x(N−1) is the congruential sequence.

According to a third aspect, an embodiment of the present inventionprovides a polar code rate matching method, including:

-   -   obtaining a congruential sequence according to a length of coded        bits of a polar code of a control signaling;    -   performing sorting processing on the congruential sequence        according to a preset rule, to obtain a reference sequence;    -   determining a mapping function according to the congruential        sequence and the reference sequence; and    -   interleaving the coded bits of the polar code of the control        signaling according to the mapping function, to generate coded        bits after interleaving.

With reference to the third aspect, in a first implementation manner ofthe third aspect, the control signaling is a broadcast signaling, andthe method further includes:

-   -   inputting, according to a preset value E, the first E bits of        the coded bits after interleaving into a cyclic buffer; or    -   performing order-reversing processing on the coded bits after        interleaving, and inputting, according to a preset value E, the        first E bits of the coded bits after order-reversing processing        into a cyclic buffer.

With reference to the third aspect and the foregoing implementationmanner of the third aspect, in a second implementation manner of thethird aspect, the obtaining a congruential sequence according to alength of coded bits of a polar code of a control signaling includes:

-   -   determining the congruential sequence according to the following        formula:

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0, 1, . . . , (N−2),

-   -   where N is the length of the coded bits of the polar code of the        control signaling, x₀, a, c, and m are particular parameters,        and x(0), x(1), . . . , x(N−1) is the congruential sequence.

With reference to the third aspect and the foregoing implementationmanners of the third aspect, in a third implementation manner of thethird aspect, a=7⁵, c=0, and m=2³¹−1.

With reference to the third aspect and the foregoing implementationmanners of the third aspect, in a fourth implementation manner of thethird aspect, the control signaling includes but is not limited to oneof the following control channels: a physical downlink control channel(PDCCH), a physical broadcast channel (PBCH), or a physical uplinkcontrol channel (PUCCH).

With reference to the third aspect and the foregoing implementationmanners of the third aspect, in a fifth implementation manner of thethird aspect, when N=128, the mapping function is:

-   -   {0, 112, 35, 14, 48, 1, 99, 54, 28, 120, 126, 46, 114, 110, 43,        32, 81, 18, 113, 63, 75, 38, 64, 7, 15, 37, 19, 70, 27, 12, 34,        50, 17, 86, 3, 68, 98, 23, 111, 62, 57, 61, 89, 59, 13, 56, 66,        107, 47, 41, 124, 30, 2, 49, 44, 88, 65, 45, 123, 104, 10, 85,        102, 103, 122, 91, 121, 58, 73, 60, 26, 8, 55, 105, 94, 82, 115,        69, 74, 83, 106, 95, 9, 108, 53, 90, 29, 11, 36, 42, 87, 39,        101, 76, 4, 67, 93, 31, 97, 119, 100, 72, 6, 5, 22, 118, 25,        117, 125, 92, 80, 77, 21, 79, 116, 33, 20, 71, 52, 109, 84, 51,        96, 24, 40, 78, 16, 127}.

With reference to the third aspect and the foregoing implementationmanners of the third aspect, in a sixth implementation manner of thethird aspect, when N=256, the mapping function is:

-   -   {0, 188, 112, 128, 183, 35, 150, 14, 48, 149, 148, 154, 130, 1,        229, 152, 131, 197, 182, 248, 253, 99, 54, 245, 231, 165, 28,        226, 120, 132, 136, 185, 168, 196, 187, 200, 159, 211, 147, 126,        46, 157, 114, 110, 210, 43, 32, 81, 18, 113, 63, 158, 75, 222,        38, 170, 219, 208, 237, 220, 252, 64, 137, 230, 216, 133, 7,        192, 218, 15, 37, 217, 19, 70, 27, 173, 155, 12, 34, 239, 50,        207, 175, 169, 223, 242, 240, 17, 161, 86, 3, 68, 98, 23, 145,        111, 62, 189, 202, 57, 61, 89, 59, 13, 56, 66, 199, 167, 214,        179, 215, 221, 107, 47, 41, 124, 234, 30, 2, 49, 44, 88, 201,        65, 195, 205, 45, 123, 104, 10, 85, 193, 102, 177, 103, 122,        225, 241, 181, 227, 91, 172, 121, 58, 142, 174, 73, 134, 60,        250, 180, 26, 8, 55, 236, 105, 94, 235, 194, 82, 162, 160, 243,        115, 69, 74, 83, 106, 191, 95, 232, 9, 108, 206, 53, 212, 209,        90, 29, 11, 139, 36, 42, 87, 39, 178, 101, 144, 151, 138, 247,        76, 4, 238, 143, 67, 146, 93, 254, 31, 198, 97, 119, 100, 171,        163, 204, 72, 6, 5, 22, 118, 190, 233, 141, 213, 25, 117, 125,        92, 246, 153, 80, 186, 135, 77, 251, 21, 79, 249, 116, 203, 164,        129, 33, 20, 71, 184, 52, 244, 109, 84, 51, 96, 24, 255, 40,        224, 176, 78, 140, 228, 16, 127, 166, 156}.

According to a fourth aspect, an embodiment of the present inventionprovides a polar code rate matching apparatus, including:

-   -   an obtaining unit, configured to obtain a congruential sequence        according to a length of coded bits of a polar code of a control        signaling;    -   a sorting unit, configured to perform sorting processing on the        congruential sequence according to a preset rule, to obtain a        reference sequence;    -   a determining unit, configured to determine a mapping function        according to the congruential sequence and the reference        sequence; and    -   an interleaving unit, configured to interleave the coded bits of        the polar code of the control signaling according to the mapping        function, to generate coded bits after interleaving.

With reference to the fourth aspect, in a first implementation manner ofthe fourth aspect, the control signaling is a broadcast signaling, andthe rate matching apparatus further includes a capturing unit, where thecapturing unit is configured to:

-   -   input, according to a preset value E, the first E bits of the        coded bits after interleaving into a cyclic buffer; or    -   perform order-reversing processing on the coded bits after        interleaving, and input, according to a preset value E, the        first E bits of the coded bits after order-reversing processing        into a cyclic buffer.

With reference to the fourth aspect and the foregoing implementationmanner of the fourth aspect, in a second implementation manner of thefourth aspect, the obtaining unit is configured to determine thecongruential sequence according to the following formula:

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]modm,

where

n=0,1, . . . , (N−2),

-   -   where N is the length of the coded bits of the polar code of the        control signaling, x₀, a, c, and m are particular parameters,        and x(0) x(1), . . . , x(N−1) is the congruential sequence.

With reference to the fourth aspect and the foregoing implementationmanners of the fourth aspect, in a third implementation manner of thefourth aspect, a=7⁵, c=0, and m2³¹−1.

With reference to the fourth aspect and the foregoing implementationmanners of the fourth aspect, in a fourth implementation manner of thefourth aspect, the control signaling includes but is not limited to oneof the following control channels: a physical downlink control channel(PDCCH), a physical broadcast channel (PBCH), or a physical uplinkcontrol channel (PUCCH).

With reference to the fourth aspect and the foregoing implementationmanners of the fourth aspect, in a third implementation manner of thefourth aspect, when N=128, the mapping function is:

-   -   {0, 112, 35, 14, 48, 1, 99, 54, 28, 120, 126, 46, 114, 110, 43,        32, 81, 18, 113, 63, 75, 38, 64, 7, 15, 37, 19, 70, 27, 12, 34,        50, 17, 86, 3, 68, 98, 23, 111, 62, 57, 61, 89, 59, 13, 56, 66,        107, 47, 41, 124, 30, 2, 49, 44, 88, 65, 45, 123, 104, 10, 85,        102, 103, 122, 91, 121, 58, 73, 60, 26, 8, 55, 105, 94, 82, 115,        69, 74, 83, 106, 95, 9, 108, 53, 90, 29, 11, 36, 42, 87, 39,        101, 76, 4, 67, 93, 31, 97, 119, 100, 72, 6, 5, 22, 118, 25,        117, 125, 92, 80, 77, 21, 79, 116, 33, 20, 71, 52, 109, 84, 51,        96, 24, 40, 78, 16, 127}.

With reference to the fourth aspect and the foregoing implementationmanners of the fourth aspect, in a third implementation manner of thefourth aspect, when N=256, the mapping function is:

-   -   {0, 188, 112, 128, 183, 35, 150, 14, 48, 149, 148, 154, 130, 1,        229, 152, 131, 197, 182, 248, 253, 99, 54, 245, 231, 165, 28,        226, 120, 132, 136, 185, 168, 196, 187, 200, 159, 211, 147, 126,        46, 157, 114, 110, 210, 43, 32, 81, 18, 113, 63, 158, 75, 222,        38, 170, 219, 208, 237, 220, 252, 64, 137, 230, 216, 133, 7,        192, 218, 15, 37, 217, 19, 70, 27, 173, 155, 12, 34, 239, 50,        207, 175, 169, 223, 242, 240, 17, 161, 86, 3, 68, 98, 23, 145,        111, 62, 189, 202, 57, 61, 89, 59, 13, 56, 66, 199, 167, 214,        179, 215, 221, 107, 47, 41, 124, 234, 30, 2, 49, 44, 88, 201,        65, 195, 205, 45, 123, 104, 10, 85, 193, 102, 177, 103, 122,        225, 241, 181, 227, 91, 172, 121, 58, 142, 174, 73, 134, 60,        250, 180, 26, 8, 55, 236, 105, 94, 235, 194, 82, 162, 160, 243,        115, 69, 74, 83, 106, 191, 95, 232, 9, 108, 206, 53, 212, 209,        90, 29, 11, 139, 36, 42, 87, 39, 178, 101, 144, 151, 138, 247,        76, 4, 238, 143, 67, 146, 93, 254, 31, 198, 97, 119, 100, 171,        163, 204, 72, 6, 5, 22, 118, 190, 233, 141, 213, 25, 117, 125,        92, 246, 153, 80, 186, 135, 77, 251, 21, 79, 249, 116, 203, 164,        129, 33, 20, 71, 184, 52, 244, 109, 84, 51, 96, 24, 255, 40,        224, 176, 78, 140, 228, 16, 127, 166, 156}.

Based on the foregoing technical solutions, when a broadcast signaling(such as a PBCH) is sent, mapping is first performed according toreliability of information bits in a polar code, and then polar codeencoding is performed on bits after mapping. In this way, useful bits inthe broadcast signaling can be prevented from being mapped tolow-reliability information bits, thereby improving encoding performanceof the polar code.

BRIEF DESCRIPTION OF DRAWINGS

To describe technical solutions in embodiments of the present inventionmore clearly, the following briefly describes the accompanying drawingsfor describing the embodiments of the present invention. Theaccompanying drawings in the following description show merely someembodiments of the present invention, and a person of ordinary skill inthe art may still derive other drawings from these accompanying drawingswithout creative efforts.

FIG. 1 shows a wireless communications system according to embodimentsof this specification;

FIG. 2 shows a schematic block diagram of a system that is used for apolar code encoding method and that is applicable to the presentinvention in a wireless communications environment;

FIG. 3 is a schematic flowchart of a polar code encoding methodaccording to an embodiment of the present invention;

FIG. 4 is a schematic block diagram of a polar code encoding apparatusaccording to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an access terminal helpful inperforming the foregoing polar code encoding method in a wirelesscommunications system;

FIG. 6 is a schematic diagram of a system helpful in performing theforegoing polar code encoding method in a wireless communicationsenvironment;

FIG. 7 shows a system in which a polar code encoding method can be usedin a wireless communications environment;

FIG. 8 is a schematic flowchart of a polar code rate matching methodaccording to an embodiment of the present invention; and

FIG. 9 is a schematic block diagram of a polar code rate matchingapparatus according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following clearly describes technical solutions in embodiments ofthe present invention with reference to the accompanying drawings. Thedescribed embodiments are a part rather than all of the embodiments ofthe present invention. All other embodiments obtained by a person ofordinary skill in the art based on the embodiments of the presentinvention without creative efforts shall fall within the protectionscope of the present invention.

Terminologies such as “component”, “module”, and “system” used in thisspecification are used to indicate computer-related entities, hardware,firmware, combinations of hardware and software, software, or softwarebeing executed. For example, a component may be, but is not limited to,a process that runs on a processor, a processor, an object, anexecutable file, a thread of execution, a program, and/or a computer.Both a computing device and an application that runs on the computingdevice may be components. One or more components may reside within aprocess and/or a thread of execution, and a component may be located onone computer and/or distributed between two or more computers. Inaddition, these components may be executed from variouscomputer-readable media that store various data structures. For example,the components may communicate using a local and/or remote process andaccording to, for example, a signal having one or more data packets (forexample, data from one component interacting with another component in alocal system, a distributed system, and/or across a network such as theInternet interacting with other systems using the signal).

In addition, the embodiments are described with reference to an accessterminal. An access terminal may also be referred to as a system, asubscriber unit, a subscriber station, a mobile station, a mobile, aremote station, a remote terminal, a mobile device, a user terminal, aterminal, a wireless communications device, a user agent, a userapparatus, or UE (user equipment). The access terminal may be a cellularphone, a cordless phone, a SIP (Session Initiation Protocol) phone, aWLL (wireless local loop) station, a PDA (personal digital assistant), ahandheld device having a wireless communication function, a computingdevice, or another processing device connected to a wireless modem. Inaddition, the embodiments are described with reference to a basestation. A base station can be used to communicate with a mobile device;and the base station may be a base transceiver station (BTS) in GlobalSystem for Mobile communication (GSM) or Code Division Multiple Access(CDMA); or may be a NodeB (NB) in Wideband Code Division Multiple Access(WCDMA); or may further be an evolved Node B (eNB or eNodeB) in LongTerm Evolution (LTE), a relay station or an access point, a base stationdevice in a future 5G network, or the like.

In addition, aspects or features of the present invention may beimplemented as a method, an apparatus or a product that uses standardprogramming and/or engineering technologies. The term “product” used inthis application covers a computer program that can be accessed from anycomputer readable component, carrier or medium. For example, thecomputer readable medium may include but is not limited to: a magneticstorage component (for example, a hard disk, a floppy disk or a magnetictape), an optical disc (for example, a Compact Disk (CD), a DigitalVersatile Disk (DVD), a smart card and a flash memory component (forexample, Erasable Programmable Read-Only Memory (EPROM), a card, astick, or a key drive). In addition, various storage media described inthis specification may indicate one or more devices and/or othermachine-readable media that is used to store information. The term“machine readable media” may include but is not limited to a radiochannel, and various other media that can store, contain and/or carry aninstruction and/or data.

FIG. 1 shows a wireless communications system 100 according toembodiments of this specification. The system 100 includes a basestation 102. The base station 102 may include multiple antenna groups.For example, one antenna group may include an antenna 104 and an antenna106, another antenna group may include an antenna 108 and an antenna110, and an additional group may include an antenna 112 and an antenna114. For each antenna group, two antennas are shown; however, more orfewer antennas may be used for each group. The base station 102 mayadditionally include a transmitter chain and a receiver chain, and aperson of ordinary skill in the art may understand that both thetransmitter chain and the receiver chain may include multiple components(for example, a processor, a modulator, a multiplexer, a demodulator, ademultiplexer, and an antenna) related to signal sending and receiving.

The base station 102 may communicate with one or more access terminals(for example, an access terminal 116 and an access terminal 122).However, it may be understood that the base station 102 may communicatewith basically any quantity of access terminals similar to the accessterminal 116 and the access terminal 122. The access terminal 116 andthe access terminal 122 may be, for example, a cellular phone, asmartphone, a portable computer, a handheld communications device, ahandheld computing device, a satellite radio apparatus, a globalpositioning system, a PDA, and/or any other suitable device configuredto perform communication in the wireless communications system 100. Asshown in the figure, the access terminal 116 communicates with theantenna 112 and the antenna 114, and the antenna 112 and the antenna 114send information to the access terminal 116 using a forward link 118,and receive information from the access terminal 116 using a reverselink 120. In addition, the access terminal 122 communicates with theantenna 104 and the antenna 106, and the antenna 104 and the antenna 106send information to the access terminal 122 using a forward link 124,and receive information from the access terminal 122 using a reverselink 126. In an FDD (frequency division duplex) system, for example, theforward link 118 may use a frequency band different from a frequencyband used by the reverse link 120, and the forward link 124 may use afrequency band different from a frequency band used by the reverse link126. In addition, in a TDD (time division duplex) system, the forwardlink 118 and the reverse link 120 may use a same frequency band, and theforward link 124 and the reverse link 126 may use a same frequency band.

Each antenna group and/or an area designed for communication is referredto as a sector of the base station 102. For example, an antenna groupmay be designed to communicate with an access terminal in a sector incoverage of the base station 102. In communication by means of theforward link 118 and the forward link 124, a transmit antenna of thebase station 102 may improve, by means of beamforming, signal-to-noiseratios of the forward link 118 and the forward link 124 for the accessterminal 116 and the access terminal 122. In addition, compared withsending, by the base station using a single antenna, information to allaccess terminals of the base station, when the base station 102 sends,by means of beamforming, information to the access terminal 116 and theaccess terminal 122 that are distributed randomly in related coverage,less interference is caused to a mobile device in a neighboring cell.

In a given time, the base station 102, the access terminal 116, and/orthe access terminal 122 may be a wireless communications apparatus forsending and/or a wireless communications apparatus for receiving. Whensending data, the wireless communications apparatus for sending mayencode the data for transmission. The wireless communications apparatusfor sending may have (for example, generate, obtain, or save in amemory) a particular quantity of information bits to be sent, using achannel, to the wireless communications apparatus for receiving. Theinformation bits may be included in a transport block (or multipletransport blocks) of data, and the transport block may be segmented toproduce multiple code blocks. In addition, the wireless communicationsapparatus for sending may encode each code block using a polar codeencoder (which is not shown), so as to improve data transmissionreliability, and further ensure communication quality.

FIG. 2 shows a schematic block diagram of a system that is used for apolar code encoding method and that is applicable to the presentinvention in a wireless communications environment. The system 200includes a wireless communications device 202. As shown in the figure,the wireless communications device 202 sends data using a channel.Although the figure shows that the wireless communications device 202sends data, the wireless communications device 202 may also receive datausing a channel (for example, the wireless communications device 202 maysimultaneously send and receive data, or the wireless communicationsdevice 202 may send and receive data at different moments, or thewireless communications device 202 may simultaneously send and receivedata, and may also send and receive data at different moments). Thewireless communications device 202 may be, for example, a base station(for example, the base station 102 in FIG. 1) or an access terminal (forexample, the access terminal 116 in FIG. 1 or the access terminal 122 inFIG. 1).

The wireless communications device 202 may include a polar code encoder204, a rate matching apparatus 205, and a transmitter 206. Optionally,when the wireless communications device 202 receives data using achannel, the wireless communications device 202 may further include areceiver. The receiver may independently exist, or may be integratedwith the transmitter 206 to form a transceiver.

The polar code encoder 204 is configured to encode data to betransferred from the wireless communications device 202, to obtain apolar code after encoding.

In this embodiment of the present invention, the polar code encoder 204is configured to: map M reserved bits of a broadcast signalingrespectively to M low-reliability information bits in K information bitsof a polar code, and map remaining bits of the broadcast signaling toremaining information bits of the K information bits, to obtain bitsafter mapping, where M<K, and both M and K are positive integers; andperform polar code encoding on the bits after mapping, to obtain codedbits after encoding.

In addition, the transmitter 206 may subsequently transmit, on achannel, an output bit that has been processed by the rate matchingapparatus 205 where rate matching has been performed. For example, thetransmitter 206 may send related data to another different wirelesscommunications apparatus (which is not shown).

A specific processing process of the polar code encoder is described indetail below. It should be noted that these examples are merely intendedto help a person skilled in the art to better understand the embodimentsof the present invention, and are not intended to limit the scope of theembodiments of the present invention.

FIG. 3 is a schematic flowchart of a polar code encoding methodaccording to an embodiment of the present invention. The method shown inFIG. 3 may be performed by a wireless communications device, forexample, the polar code encoder 204 in the wireless communicationsdevice shown in FIG. 2. The encoding method shown in FIG. 3 includes thefollowing steps.

301. Map M reserved bits of a broadcast signaling respectively to Mlow-reliability information bits in K information bits of a polar code,and map remaining bits of the broadcast signaling to remaininginformation bits of the K information bits, to obtain bits aftermapping, where M<K, and both M and K are positive integers.

It should be understood that, the broadcast signaling refers tosignaling carried on a broadcast channel (for example, a physicalbroadcast channel (PBCH)). The broadcast signaling generally includesmultiple reserved bits that actually carry no useful information.Therefore, in a polar code encoding process, the reserved bits aremapped to low-reliability information bits, so that correct decoding ofthe broadcast signaling is not affected even if the reserved bits changein a transmission process.

It should also be understood that, this embodiment of the presentinvention does not limit a form of a reliability metric. For example, areference may be made to an existing reliability metric for a polarcode, such as a bit capacity, a Bhattacharyya parameter such as aBhattacharyya distance, or an error probability.

For example, it is assumed that a result obtained after a cyclicredundancy check (CRC) is performed on a broadcast signaling (signalingcarried on a PBCH channel) is a₀, a₁, . . . , a₁₃, a₁₄, . . . , a₂₃,a₂₄, . . . , and a₃₉, where a₁₄, . . . , and a₂₃ are reserved bits (thequantity is 10), and a₂₄, . . . , and a₃₉ correspond to check bits(which may include a mask). It is assumed that 10 low-reliabilityinformation bits in a polar code are respectively {79, 106, 55, 105, 92,102, 90, 101, 47, 89}. Therefore, when the foregoing 10 reserved bitsare mapped to the foregoing 10 low-reliability information bits, thatu(79)=a₁₄, u(106)=a15, u(55)=a₁₆, u(105)=a₁₇, u(92)=a₁₈, u(102)=a₁₉,u(90)=a₂₀, u(101)=a₂₁, u(47)=a₂₂, and u(89)=a₂₃ may be achieved with aninterleaver, so as to complete a process of mapping the reserved bits tothe information bits. Similarly, when remaining bits of the broadcastsignaling are mapped to remaining information bits of the polar code,refer to the foregoing method. To avoid repetition, details are notdescribed herein.

302. Perform polar code encoding on the bits after mapping, to obtaincoded bits after encoding.

For example, when preparing to send a broadcast signaling using a PBCHchannel, the wireless communications device may first perform polar codeencoding on the broadcast signaling. Encoding output of a polar code maybe represented by formula (1):

x ₁ ^(N) =u ₁ ^(N) G _(N)  (1),

-   -   where u₁ ^(N)={u₁, u₂, . . . , u_(N)} is a binary row vector        with a length of N; and G_(N) is an N*N matrix,        G_(N)=B_(N)=B_(N)        , where N is a length of coded bits after encoding, and n≧0; and        herein,

${F = \begin{bmatrix}1 & 0 \\1 & 1\end{bmatrix}},$

B_(N) is a transposed matrix,

is a kronecker power, and it is defined as:

=F

In a polar code encoding process, some bits in u₁ ^(N) are used to carryinformation (that is, information that needs to be sent to a receiveend), where the bits are referred to as information bits, and an indexset of the bits is denoted as A. Remaining bits have fixed values, andare referred to as frozen bits, and for example, usually may be set to0.

According to the method in this embodiment of the present invention,reserved bits of a broadcast signaling are mapped, according to a lengthof the reserved bits, that is, a quantity M of the reserved bits, to Minformation bits with lowest reliability of a polar code, and remainingbits of the broadcast signaling are mapped to remaining information bitsof the polar code. Then, a polar code after encoding may be obtainedaccording to the encoding process shown in formula (1). That is, codedbits after encoding are obtained.

A polar code after encoding that is output after encoding processingperformed by the polar code encoder may be simplified as: x₁^(N)=u_(A)G_(N)(A), where u_(A) is a set of information bits in u₁ ^(N);u_(A) is a row vector with a length of K; K is a quantity of theinformation bits; G_(N)(A) is a submatrix that is formed by rowscorresponding to indices in the set A and that is in G_(N); and G_(N)(A)is a K*N matrix.

Based on the foregoing technical solution, when a broadcast signaling issent, mapping is first performed according to reliability of informationbits in a polar code, and then polar code encoding is performed on bitsafter mapping. In this way, useful bits in the broadcast signaling canbe prevented from being mapped to low-reliability information bits,thereby improving broadcast signaling transmission reliability.

Optionally, in an embodiment, the M low-reliability information bitsinclude M information bits with reliability lower than a presetthreshold, or the M low-reliability information bits include Minformation bits with lowest reliability in the K information bits.

Optionally, in another embodiment, before the M reserved bits of thebroadcast signaling are respectively mapped to the M low-reliabilityinformation bits in the K information bits of the polar code, the Kinformation bits may be sorted according to reliability of the Kinformation bits. In this case, when the M reserved bits of thebroadcast signaling are respectively mapped to the M low-reliabilityinformation bits in the K information bits of the polar code, the Mreserved bits are respectively mapped to the M low-reliabilityinformation bits in the K information bits according to a sortingresult.

For example, a description is made using an example in which a polarcode has a code length of 128 bits. The polar code includes 40information bits. The 40 information bits are sorted according toreliability in descending order, and indices after sorting are obtainedas follows:

-   -   {127, 126, 125, 23, 119, 111, 95, 124, 122, 63, 121, 118, 117,        115, 110, 109, 107, 94, 93, 103, 91, 62, 120, 87, 61, 116, 114,        59, 108, 113, 79, 106, 55, 105, 92, 102, 90, 101, 47, 89}.

It is assumed that a broadcast signaling has a length of 40 bits, andincludes 10 reserved bits. Therefore, the 10 reserved bits need to berespectively mapped to corresponding information bits {79, 106, 55, 105,92, 102, 90, 101, 47, 89}. Remaining bits of the broadcast signaling aremapped to other information bits different from the foregoing 10 bits.

Optionally, in another embodiment, the reliability of one of the Kinformation bits is determined according to a bit capacity, aBhattacharyya parameter such as a Bhattacharyya distance, or an errorprobability.

For example, when a bit capacity is used as a reliability metric of aninformation bit, a bit capacity of each information bit of a polar codemay be first determined, and the bit capacity is used to indicatereliability of the information bit. A bit with a larger bit capacity hashigher reliability.

Alternatively, when a Bhattacharyya parameter is used as a reliabilitymetric of an information bit, a Bhattacharyya parameter of eachinformation bit of a polar code may be first determined, and theBhattacharyya parameter is used to indicate reliability of theinformation bit. An information bit with a smaller Bhattacharyyaparameter has higher reliability.

Optionally, in another embodiment, after polar code encoding isperformed on the bits after mapping to obtain the coded bits afterencoding, sorted congruential interleaving may be performed on the codedbits after encoding, to obtain coded bits after interleaving. Then,according to a preset value E, the first E bits of the coded bits afterinterleaving are input into a cyclic buffer. Alternatively,order-reversing processing is performed on the coded bits afterinterleaving; and according to a preset value E, the first E bits of thecoded bits after order-reversing processing are input into a cyclicbuffer.

It should be understood that, the preset value E is related to a frameformat of the broadcast signaling. Therefore, this embodiment of thepresent invention can further improve encoding efficiency.

For example, the interleaving process may be performed by the ratematching apparatus 205 in the wireless communications device 202 shownin FIG. 2. The polar code encoder 204 may perform polar code encodingaccording to the foregoing method, and output coded bits after encoding.The rate matching apparatus 205 performs sorted congruentialinterleaving on the coded bits output by the polar code encoder 204. Thefirst E bits after interleaving are captured and used as final outputresults, and output to a cyclic buffer. Generally, the cyclic buffer islocated in the transmitter 206 shown in FIG. 2. Therefore, thetransmitter transmits data in the cyclic buffer.

TABLE 1 Relative performance gain between a polar code Length of a listand an LTE tail-biting convolution code 16 0.8 dB 32 1.0 dB 64 1.2 dB128 1.4 dB 1024 1.9 dB

Table 1 shows relative performance gains between a PBCH channel based ona polar code and a PBCH channel based on a tail-biting convolution in anLTE standard when a target packet error rate is 1% and lengths of Listsare different. It can be seen from Table 1 that, for same decodingcomplexity, compared with the PBCH solution based on the tail-bitingconvolution code in the LTE standard, the proposed PBCH solution basedon the polar code has at least a gain of 0.8 dB.

Optionally, in another embodiment, when sorted congruential interleavingis performed on the coded bits after encoding, to obtain the coded bitsafter interleaving, a congruential sequence may be first obtainedaccording to a length of the coded bits after encoding. Then, sortingprocessing is performed on the congruential sequence according to apreset rule, to obtain a reference sequence. Therefore, a mappingfunction may be determined according to the congruential sequence andthe reference sequence; and interleaving is performed on the coded bitsafter encoding according to the mapping function, to obtain the codedbits after interleaving.

Optionally, in another embodiment, when the congruential sequence isobtained according to the length of coded bits after encoding, thecongruential sequence may be determined according to the followingformula (2):

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0,1, . . . , (N−2)  (2),

where N is the length of the coded bits of the polar code afterencoding, x₀, a, c, and m are particular parameters, and x(0), x(1), . .. , x(N−1) is the congruential sequence.

It should be understood that, that N is the length of the coded bits ofthe polar code after encoding means that N is a code length of the polarcode.

It is assumed that Q is a given positive integer. If two integers A andB are divided by Q, and obtained remainders are the same, A and B arecongruential to the modulus Q. Formula (2) represents a linearcongruential method, m represents a modulus, and m>0; a represents amultiplier; c represents an increment; and x(0) represents an initialvalue.

Optionally, in another embodiment, x₀=483, a=7⁵, c=0 and m=2 ³¹−1.

In this embodiment of the present invention, a congruential sequence maybe generated using the following program based on matlab:

function [seq_x]=multiplieCongru_interg(length, initial) statement 1seq_x(1)=initial; statement 2 a=7{circumflex over ( )}5; statement 3c=0; statement 4 m=2{circumflex over ( )}31−1; statement 5 for k=1:(length−1); statement 6 seq_x(k+1)=mod(a*seq_x(k)+c, m); statement 7 end

A specific description of the program is as follows:

-   -   the statement 1 defines a function multiplieCongru_interg that        implements a congruential sequence, where a return value of the        function is seq_x; initial is an initial value of the        congruential sequence, and is an input parameter of the        function; and length is a quantity of elements in the        congruential sequence, that is, length=N, and N is a code length        of a polar code;    -   the statement 2 defines the first element in the congruential        sequence, that is, seq_x(1) is a preset initial value;    -   the statement 3 defines that a parameter a=7⁵;    -   the statement 4 defines that a parameter c=0;    -   the statement 5 defines that a parameter m=2³¹−1;    -   the statement 6 defines that a value range of k is [1,        length−1]; and    -   the statement 7 defines that seq_x(k+1) is a result of a*seq_x        (k)+c mod m.

It should be noted that, sequence numbers of an array in matlab startfrom 1, and therefore, sequence numbers of pseudo codes in matlab startfrom 1 to N.

Afterward, the wireless communications device may perform sortingprocessing on the foregoing determined congruential sequence inascending order (an example of the preset rule). In this embodiment ofthe present invention, for example, a sort function may be used toperform the foregoing sorting processing. The sort function may berepresented as sort ([first, last]), that is, elements in [first, last]are sorted in ascending order.

Further, in this embodiment of the present invention, sorting may beperformed on the generated congruential sequence using the followingprogram based on matlab:

st2=4831; [seq_x]=multiplieCongru_interg(N, st2); [ign, p]=sort (seq_x);Interleaver_RM=p;

Therefore, the congruential sequence after the sorting processing may beused as the reference sequence.

Therefore, the mapping function may be determined according to theforegoing obtained congruential sequence and reference sequence. Sortingprocessing is performed on the elements in the congruential sequence;therefore, the foregoing mapping function may be determined according topositions of the elements in the congruential sequence and the referencesequence.

For example but not for limitation, if a sequence A is [0, 7, 1], asequence B that is obtained after sorting is performed on the sequence Ain ascending order is [0, 1, 7]. Therefore, a mapping rule (or, amapping function) p from the sequence A to the sequence B may berepresented as [0, 2, 1]. That is, the first element (with a sequencenumber 0) in the sequence B is the first element (with a sequence number0) in the sequence A; the second element (with a sequence number 1) inthe sequence B is the third element (with a sequence number 2) in thesequence A; and the third element (with a sequence number 2) in thesequence B is the second element (with a sequence number 1) in thesequence A.

Similarly, the mapping function may be obtained according to theforegoing obtained reference sequence and congruential sequence.Therefore, interleaving processing may be performed on the polar codeafter encoding according to the foregoing obtained mapping function.

For example but not for limitation, if the mapping function p is [0, 2,1], a bit value of the first bit (with a sequence number 0) of the polarcode after interleaving is a bit value of the first bit (with a sequencenumber 0) of the polar code before interleaving processing; a bit valueof the second bit (with a sequence number 1) of the polar code afterinterleaving processing is a bit value of the third bit (with a sequencenumber 2) of the polar code before interleaving processing; and a bitvalue of the third bit (with a sequence number 2) of the polar codeafter interleaving processing is a bit value of the second bit (with asequence number 1) of the polar code before interleaving processing.

FIG. 4 is a schematic block diagram of a polar code encoding apparatusaccording to an embodiment of the present invention. The encodingapparatus 400 in FIG. 4 may be located in a base station or an accessterminal (for example, the base station 102 or the access terminal 116),and includes a mapping unit 401 and an encoding unit 402.

The mapping unit 401 is configured to: map M reserved bits of abroadcast signaling respectively to M low-reliability information bitsin K information bits of a polar code, and map remaining bits of thebroadcast signaling to remaining information bits of the K informationbits, to obtain bits after mapping, where M<K, and both M and K arepositive integers.

It should be understood that, the broadcast signaling refers tosignaling carried on a broadcast channel (for example, a PBCH). Thebroadcast signaling generally includes multiple reserved bits thatactually carry no useful information. Therefore, in a polar codeencoding process, the reserved bits are mapped to low-reliabilityinformation bits, so that correct decoding of the broadcast signaling isnot affected even if the reserved bits change in a transmission process.

It should also be understood that, this embodiment of the presentinvention does not limit a form of a reliability metric. For example,reference may be made to an existing reliability metric for a polarcode, such as a bit capacity, a Bhattacharyya parameter such as aBhattacharyya distance, or an error probability.

For example, it is assumed that a result obtained after a CRC isperformed on a broadcast signaling (signaling carried on a PBCH channel)is a₀, a₁, . . . , a₁₃, a₁₄, . . . , a₂₃, a₂₄, . . . , and a₃₉, wherea₁₄, . . . , and a₂₃ are reserved bits (a quantity is 10), and a₂₄, . .. , and a₃₉ correspond to check bits (which may include a mask). It isassumed that 10 low-reliability information bits in a polar code arerespectively {79, 106, 55, 105, 92, 102, 90, 101, 47, 89}. Therefore,when the foregoing 10 reserved bits are mapped to the foregoing 10low-reliability information bits, that u(79)=a₁₄, u(106)=a₁₅, u(55)=a₁₆,u(105)=a₁₇, u(92)=a₁₈, u(102)=a₁₉, u(90)=a₂₀, u(101)=a₂₁, u(47)=a₂₂, andu(89)=a₂₃ may be achieved using an interleaver, so as to complete aprocess of mapping the reserved bits to the information bits. Similarly,when remaining bits of the broadcast signaling are mapped to remaininginformation bits of the polar code, refer to the foregoing method. Toavoid repetition, details are not described herein.

The encoding unit 402 is configured to perform polar code encoding onthe bits after mapping, to obtain coded bits after encoding.

For the process in which the encoding unit performs polar code encodingon the bits after mapping, refer to the description of the foregoingembodiments. To avoid repetition, details are not described herein.

Based on the foregoing technical solution, when a broadcast signaling issent, mapping is first performed according to reliability of informationbits in a polar code, and then polar code encoding is performed on bitsafter mapping. In this way, useful bits in the broadcast signaling canbe prevented from being mapped to low-reliability information bits,thereby improving broadcast signaling transmission reliability.

Optionally, in an embodiment, the M low-reliability information bitsinclude M information bits with reliability lower than a presetthreshold, or the M low-reliability information bits include Minformation bits with lowest reliability in the K information bits.

Optionally, in another embodiment, the encoding apparatus 400 furtherincludes a sorting unit 403.

The sorting unit 403 is configured to sort the K information bitsaccording to reliability of the K information bits.

In this case, the encoding unit 402 is configured to map, according to asorting result, the M reserved bits respectively to the Mlow-reliability information bits in the K information bits.

For example, a description is made using an example in which a polarcode has a code length of 128 bits. The polar code includes 40information bits. The 40 information bits are sorted according toreliability in descending order, and indices after sorting are obtainedas follows:

-   -   {127, 126, 125, 23, 119, 111, 95, 124, 122, 63, 121, 118, 117,        115, 110, 109, 107, 94, 93, 103, 91, 62, 120, 87, 61, 116, 114,        59, 108, 113, 79, 106, 55, 105, 92, 102, 90, 101, 47, 89}.

It is assumed that a broadcast signaling has a length of 40 bits, andincludes 10 reserved bits. Therefore, the 10 reserved bits need to berespectively mapped to corresponding information bits {79, 106, 55, 105,92, 102, 90, 101, 47, 89}. Remaining bits of the broadcast signaling aremapped to other information bits different from the foregoing 10 bits.

Optionally, in another embodiment, the reliability of one of the Kinformation bits is determined according to a bit capacity, aBhattacharyya parameter such as a Bhattacharyya distance, or an errorprobability.

For example, when a bit capacity is used as a reliability metric of aninformation bit, a bit capacity of each information bit of a polar codemay be first determined, and the bit capacity is used to indicatereliability of the information bit. A bit with a larger bit capacity hashigher reliability.

Alternatively, when a Bhattacharyya parameter is used as a reliabilitymetric of an information bit, a Bhattacharyya parameter of eachinformation bit of a polar code may be first determined, and theBhattacharyya parameter is used to indicate reliability of theinformation bit. An information bit with a smaller Bhattacharyyaparameter has higher reliability.

Optionally, in another embodiment, the encoding apparatus 400 furtherincludes an interleaving unit 404 and a capturing unit 405. Theinterleaving unit 404 and the capturing unit 405 may be located in therate matching apparatus 205 of the wireless communications device 202shown in FIG. 2. Therefore, the rate matching apparatus 205 and thepolar code encoder 204 together form the polar code encoding apparatus400.

The interleaving unit 404 is configured to perform sorted congruentialinterleaving on the coded bits after encoding, to obtain coded bitsafter interleaving.

The capturing unit 405 is configured to input, according to a presetvalue E, the first E bits of the coded bits after interleaving into acyclic buffer.

Alternatively, the capturing unit 405 is configured to performorder-reversing processing on the coded bits after interleaving, andinput, according to a preset value E, the first E bits of the coded bitsafter order-reversing processing into a cyclic buffer.

It should be understood that, the preset value E is related to a frameformat of the broadcast signaling. Therefore, this embodiment of thepresent invention can further improve encoding efficiency.

Optionally, in another embodiment, the interleaving unit 404 isconfigured to obtain a congruential sequence according to a length ofthe coded bits after encoding; then, perform sorting processing on thecongruential sequence according to a preset rule, to obtain a referencesequence; determine a mapping function according to the congruentialsequence and the reference sequence; and finally, interleave the codedbits after encoding according to the mapping function, to obtain thecoded bits after interleaving.

For the process in which the interleaving unit 404 interleaves the codedbits after encoding, refer to the specific description of the foregoingembodiment. To avoid repetition, details are not described herein.

Optionally, in another embodiment, the interleaving unit 404 isconfigured to determine the congruential sequence according to thefollowing formula (3):

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0, 1, . . . , (N−2)  (3),

-   -   where N is the length of the coded bits of the polar code after        encoding, x₀, a, c, and m are particular parameters, and x(0),        x(1), . . . , x(N−1) is the congruential sequence.

It should be understood that, that N is the length of the coded bits ofthe polar code after encoding means that N is a code length of the polarcode.

It is assumed that Q is a given positive integer. If two integers A andB are divided by Q, and obtained remainders are the same, A and B arecongruential to the modulus Q. Formula (2) represents a linearcongruential method, m represents a modulus, and m>0; a represents amultiplier; c represents an increment; and x(0) represents an initialvalue.

Optionally, in another embodiment, x₀=4831, a=7⁵, c=0, and m=2³¹−1.

FIG. 5 is a schematic diagram of an access terminal helpful inperforming the foregoing polar code encoding method in a wirelesscommunications system. The access terminal 500 includes a receiver 502.The receiver 502 is configured to receive a signal from, for example, areceive antenna (which is not shown), perform a typical operation (forexample, filtering, amplification, or down-conversion) on the receivedsignal, and digitize an adjusted signal to obtain a sample. The receiver502 may be, for example, a minimum mean square error (MMSE) receiver.The access terminal 500 may further include a demodulator 504. Thedemodulator 504 may be configured to demodulate received symbols andprovide the symbols to a processor 506 for channel estimation. Theprocessor 506 may be a processor dedicated for analyzing informationreceived by the receiver 502 and/or generating information to be sent bythe transmitter 516, a processor configured to control one or morecomponents of the access terminal 500, and/or a controller configured toanalyze information received by the receiver 502, generate informationto be sent by the transmitter 516, and control one or more components ofthe access terminal 500.

The access terminal 500 may additionally include a memory 508. Thememory 508 is operatively coupled to the processor 506, and stores thefollowing data: data to be sent, received data, and any other suitableinformation related to execution of various operations and functions inthis specification. The memory 508 may additionally store a protocoland/or an algorithm related to polar code processing.

It may be understood that a data storage apparatus (for example, thememory 508) described in this specification may be a volatile memory ora non-volatile memory, or may include both a volatile memory and anon-volatile memory. For example but not for limitation, thenon-volatile memory may include: a read-only memory (ROM), aprogrammable read-only memory (Programmable ROM, PROM), an erasableprogrammable read-only memory (Erasable PROM, EPROM), an electricallyerasable programmable read-only memory (Electrically EPROM, EEPROM), ora flash memory. The volatile memory may include a random access memory(RAM), which is used as an external cache. For example but not forlimitation, RAMs in many forms such as a static random access memory(Static RAM, SRAM), a dynamic random access memory (Dynamic RAM, DRAM),a synchronous dynamic random access memory (Synchronous DRAM, SDRAM), adouble data rate synchronous dynamic random access memory (DDR SDRAM),an enhanced synchronous dynamic random access memory (Enhanced SDRAM,ESDRAM), a synchlink dynamic random access memory (Synchlink DRAM,SLDRAM), and a direct rambus random access memory (Direct Rambus RAM, DRRAM) may be used. The memory 508 in the system and the method describedin this specification intends to include, but is not limited to, thesememories and any other memory of a suitable type.

In addition, the access terminal 500 further includes a polar codeencoder 512 and a rate matching device 510. In actual application, thereceiver 502 may be further coupled to the rate matching device 510. Therate matching device 510 may be basically similar to the rate matchingapparatus 205 in FIG. 2. The polar code encoder 512 is basically similarto the polar code encoder 204 in FIG. 2.

The polar code encoder 512 may be configured to: map M reserved bits ofa broadcast signaling respectively to M low-reliability information bitsin K information bits of a polar code, and map remaining bits of thebroadcast signaling to remaining information bits of the K informationbits, to obtain bits after mapping, where M<K, and both M and K arepositive integers; and then perform polar code encoding on the bitsafter mapping, to obtain coded bits after encoding.

According to this embodiment of the present invention, when a broadcastsignaling is sent, mapping is first performed according to reliabilityof information bits in a polar code, and then polar code encoding isperformed on bits after mapping. In this way, useful bits in thebroadcast signaling can be prevented from being mapped tolow-reliability information bits, thereby improving broadcast signalingtransmission reliability.

Optionally, in an embodiment, the M low-reliability information bitsinclude M information bits with reliability lower than a presetthreshold, or the M low-reliability information bits include Minformation bits with lowest reliability in the K information bits.

Optionally, in another embodiment, the polar code encoder 512 sorts theK information bits according to reliability of the K information bits.Then, the polar code encoder 512 maps, according to a sorting result,the M reserved bits respectively to the M low-reliability informationbits in the K information bits.

Optionally, in another embodiment, the reliability of one of the Kinformation bits is determined according to a bit capacity, aBhattacharyya parameter such as a Bhattacharyya distance, or an errorprobability.

Optionally, in another embodiment, the rate matching device 510 performssorted congruential interleaving on the coded bits after encoding, toobtain coded bits after interleaving; and inputs, according to a presetvalue E, the first E bits of the coded bits after interleaving into acyclic buffer.

Alternatively, the rate matching device 510 performs sorted congruentialinterleaving on the coded bits after encoding, to obtain coded bitsafter interleaving; and performs order-reversing processing on the codedbits after interleaving, and inputs, according to a preset value E, thefirst E bits of the coded bits after order-reversing processing into acyclic buffer.

Optionally, in another embodiment, the rate matching device 510 obtainsa congruential sequence according to a length of the coded bits afterencoding; then, performs sorting processing on the congruential sequenceaccording to a preset rule, to obtain a reference sequence; determines amapping function according to the congruential sequence and thereference sequence; and finally, interleaves the coded bits afterencoding according to the mapping function, to obtain the coded bitsafter interleaving.

Optionally, in another embodiment, the rate matching device 510determines the congruential sequence according to the following formula(4):

x(0)=x₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0,1, . . . , (N−2)  (4).

-   -   where N is the length of the coded bits of the polar code after        encoding, x₀, a, c, and m are particular parameters, and x(0),        x(1), . . . , x(N−1) is the congruential sequence.

It should be understood that, that N is the length of the coded bits ofthe polar code after encoding means that N is a code length of the polarcode.

FIG. 6 is a schematic diagram of a system helpful in performing theforegoing polar code encoding method in a wireless communicationsenvironment. The system 600 includes a base station 602 (for example, anaccess point, a NodeB, or an eNB). The base station 602 has a receiver610 that receives a signal from one or more access terminals 604 usingmultiple receive antennas 606, and a transmitter 624 that transmits asignal to the one or more access terminals 604 using a transmit antenna608. The receiver 610 may receive information from the receive antennas606, and is operatively associated to a demodulator 612 that demodulatesthe received information. A demodulated symbol is analyzed by aprocessor 614 similar to the processor described in FIG. 5, theprocessor 614 is connected to a memory 616, and the memory 616 isconfigured to store data to be sent to the access terminal 604 (or adifferent base station (which is not shown)), or data received from theaccess terminal 604 (or a different base station (which is not shown)),and/or any other suitable information related to execution of variousoperations and functions in this specification. The processor 614 may befurther coupled to a polar code encoder 618 and a rate matching device620.

The polar code encoder 618 may be configured to: map M reserved bits ofa broadcast signaling respectively to M low-reliability information bitsin K information bits of a polar code, and map remaining bits of thebroadcast signaling to remaining information bits of the K informationbits, to obtain bits after mapping, where M<K, and both M and K arepositive integers; and then perform polar code encoding on the bitsafter mapping, to obtain coded bits after encoding.

According to this embodiment of the present invention, when a broadcastsignaling is sent, mapping is first performed according to reliabilityof information bits in a polar code, and then polar code encoding isperformed on bits after mapping. In this way, useful bits in thebroadcast signaling can be prevented from being mapped tolow-reliability information bits, thereby improving broadcast signalingtransmission reliability.

Optionally, in an embodiment, the M low-reliability information bitsinclude M information bits with reliability lower than a presetthreshold, or the M low-reliability information bits include Minformation bits with lowest reliability in the K information bits.

Optionally, in another embodiment, the polar code encoder 618 sorts theK information bits according to reliability of the K information bits.Then, the polar code encoder 618 maps, according to a sorting result,the M reserved bits respectively to the M low-reliability informationbits in the K information bits.

Optionally, in another embodiment, the reliability of one of the Kinformation bits is determined according to a bit capacity, aBhattacharyya parameter such as a Bhattacharyya distance, or an errorprobability.

Optionally, in another embodiment, the rate matching device 620 performssorted congruential interleaving on the coded bits after encoding, toobtain coded bits after interleaving; and inputs, according to a presetvalue E, the first E bits of the coded bits after interleaving into acyclic buffer.

Alternatively, the rate matching device 620 performs sorted congruentialinterleaving on the coded bits after encoding, to obtain coded bitsafter interleaving; and performs order-reversing processing on the codedbits after interleaving, and inputs, according to a preset value E, thefirst E bits of the coded bits after order-reversing processing into acyclic buffer.

Optionally, in another embodiment, the rate matching device 620 obtainsa congruential sequence according to a length of the coded bits afterencoding; then, performs sorting processing on the congruential sequenceaccording to a preset rule, to obtain a reference sequence; determines amapping function according to the congruential sequence and thereference sequence; and finally, interleaves the coded bits afterencoding according to the mapping function, to obtain the coded bitsafter interleaving.

Optionally, in another embodiment, the rate matching device 620determines the congruential sequence according to the following formula(5):

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0,1, . . . , (N−2)  (5),

-   -   where N is the length of the coded bits of the polar code after        encoding, x₀, a, c, and m are particular parameters, and x(0),        x(1), . . . , x(N−1) is the congruential sequence. It should be        understood that, that N is the length of the coded bits of the        polar code after encoding means that N is a code length of the        polar code.

In addition, in the system 600, a modulator 622 may multiplex a frame,so that the transmitter 624 sends information to the access terminal 604using the antenna 608. Although it is shown that the polar code encoder618, the rate matching device 620, and/or the modulator 622 are/isseparated from the processor 614, it may be understood that the polarcode encoder 618, the rate matching device 620, and/or the modulator 622may be a part of the processor 614 or multiple processors (which are notshown).

It may be understood that the embodiments described in thisspecification may be implemented by hardware, software, firmware,middleware, microcode, or a combination thereof. For hardwareimplementation, a processing unit may be implemented in one or moreapplication specific integrated circuits (ASIC), a digital signalprocessor (DSP), a digital signal processing device (DSP Device, DSPD),a programmable logic device (PLD), a field-programmable gate array(FPGA), a processor, a controller, a microcontroller, a microprocessor,and other electronic units configured to perform the functions describedin this application, or a combination thereof.

When the embodiments are implemented in software, firmware, middleware,microcode, program code, or a code segment, they may be stored in, forexample, a machine-readable medium of a storage component. The codesegment may indicate a process, a function, a subprogram, a program, aroutine, a subroutine, a module, a software group, a type, or anycombination of an instruction, a data structure, and a programstatement. The code segment may be coupled to another code segment or ahardware circuit by transferring and/or receiving information, data, anindependent variable, a parameter, or memory content. The information,the independent variable, the parameter, data, or the like may betransferred, forwarded, or sent in any suitable manner such as memorysharing, message transfer, token transfer, or network transmission.

For implementation by software, the technologies in this specificationmay be implemented by performing the functional modules (for example, aprocess and a function) in this specification. Software code may bestored in a storage unit and executed by a processor. The storage unitmay be implemented inside the processor or outside the processor, and inthe latter case, the storage unit may be coupled to the processor bymeans of communication using various means known in the art.

FIG. 7 shows a system in which a polar code encoding method can be usedin a wireless communications environment.

For example, the system 700 may at least partially reside within a basestation. According to another example, the system 700 may at leastpartially reside within an access terminal. It should be understood thatthe system 700 may be indicated as including a functional block, whichmay indicate a functional block of a function implemented by aprocessor, software, or a combination thereof (for example, firmware).The system 700 includes a logical group 702 with electronic componentsthat jointly perform an operation.

For example, the logical group 702 may be configured to: map M reservedbits of a broadcast signaling respectively to M low-reliabilityinformation bits in K information bits of a polar code, and mapremaining bits of the broadcast signaling to remaining information bitsof the K information bits, to obtain bits after mapping, where M<K, andboth M and K are positive integers. The logical group 702 may be furtherconfigured to perform polar code encoding on the bits after mapping, toobtain coded bits after encoding.

According to this embodiment of the present invention, when a broadcastsignaling is sent, mapping is first performed according to reliabilityof information bits in a polar code, and then polar code encoding isperformed on bits after mapping. In this way, useful bits in thebroadcast signaling can be prevented from being mapped tolow-reliability information bits, thereby improving broadcast signalingtransmission reliability.

In addition, the system 700 may include a memory 712. The memory 712stores instructions for performing functions related to the electroniccomponents 704, 706, and 708. Although it is shown that the electroniccomponents 704, 706, and 708 are located outside the memory 712, it maybe understood that one or more of the electronic components 704, 706,and 708 may exist inside the memory 712.

FIG. 8 is a schematic flowchart of a polar code rate matching methodaccording to an embodiment of the present invention. The method shown inFIG. 8 may be performed by a wireless communications device, forexample, the rate matching apparatus 205 in the wireless communicationsdevice shown in FIG. 2. The rate matching method shown in FIG. 8includes the following steps:

801. Obtain a congruential sequence according to a length of coded bitsof a polar code of a control signaling.

802. Perform sorting processing on the congruential sequence accordingto a preset rule, to obtain a reference sequence.

803. Determine a mapping function according to the congruential sequenceand the reference sequence.

804. Interleave the coded bits of the polar code of the controlsignaling according to the mapping function, to generate coded bitsafter interleaving.

According to the polar code rate matching method in this embodiment ofthe present invention, a congruential sequence is determined based on alength of coded bits of a polar code of a control signaling; and thecoded bits of the polar code of the control signaling are interleavedusing the congruential sequence, so that a bit sequence structure afterinterleaving can be more even, a frame error rate can be lowered, andcommunication reliability can be improved; and the method is applicableto a rate matching process for polar codes with different code lengths,and has good universality and applicability.

In step 801, a transmit end may perform, using, for example, a polarcode encoder, polar code encoding processing on information that needsto be sent to a receive end, to generate a polar code (that is, codedbits of a control signaling). The polar code is a linear block code, andis theoretically proved to be an encoding manner that can achieve aShannon capacity and has low coding-decoding complexity. Encoding outputof a polar code may be represented as follows:

x ₁ ^(N) =u ₁ ^(N) G _(N),

-   -   where u₁ ^(N)={u₁, u₂, . . . , u_(N)} is a binary row vector        with a length of N; G_(N) is an N*N matrix, and G_(N)=B_(N)        , where a code length N=2^(n), and n≧0 and herein,

${F = \begin{bmatrix}1 & 0 \\1 & 1\end{bmatrix}},$

B_(N) is a transposed matrix,

is a kronecker power, and it is defined as:

=F

In a polar code encoding process, some bits in u₁ ^(N) are used to carryinformation (that is, data information that needs to be sent to areceive end), the bits are referred to as information bits, and an indexset of the bits is denoted as A. Remaining bits have fixed values, andare referred to as frozen bits, and for example, usually may be set to0.

Therefore, a polar code bit sequence that is output after encodingprocessing performed by the polar code encoder may be simplified as: x₁^(N)=u_(A)G_(N)(A), where u_(A) is a set of information bits in u₁ ^(N);u_(A) is a row vector with a length of K; K is a quantity of theinformation bits; G_(N)(A) is a submatrix that is formed by rowscorresponding to indices in the set A and that is in G_(N); G_(N)(A) isa K*N matrix; and performance of the polar code depends on selection ofthe set A.

It should be understood that, the foregoing examples of a process ofobtaining a polar code are merely descriptions for illustration, and thepresent invention is not limited thereto. Other methods for performingencoding processing on information to obtain a bit sequence with a polarcode feature shall fall within the protection scope of the presentinvention.

It should also be understood that, the coded bits of the polar code ofthe control signaling refer to coded bits obtained by performing polarcode encoding on the control signaling.

Optionally, in an embodiment, the control signaling is a broadcastsignaling. In this case, according to a preset value E, the first E bitsof the coded bits after interleaving are input into a cyclic buffer; ororder-reversing processing is performed on the coded bits afterinterleaving, and according to a preset value E, the first E bits of thecoded bits after order-reversing processing are input into a cyclicbuffer.

Optionally, in another embodiment, when the congruential sequence isobtained according to the length of the coded bits of the polar code ofthe control signaling, the congruential sequence is determined accordingto the following formula:

x(0)=x ₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0, 1, . . . , (N−2),

-   -   where N is the length of the coded bits of the polar code of the        control signaling, x₀, a, c, and m are particular parameters,        and x(0), x(1), . . . , x(N−1) is the congruential sequence. It        should be understood that, that N is the length of the coded        bits of the polar code of the control signaling means that N is        a code length of the polar code.

It is assumed that Q is a given positive integer. If two integers A andB are divided by Q, and obtained remainders are the same, A and B arecongruential to the modulus Q. Formula (2) represents a linearcongruential method, m represents a modulus, and m>0; a represents amultiplier; c represents an increment; and x(0) represents an initialvalue.

Therefore, the mapping function may be determined according to theforegoing obtained congruential sequence and reference sequence. Sortingprocessing is performed on elements in the congruential sequence;therefore, the foregoing mapping function may be determined according topositions of the elements in the congruential sequence and the referencesequence.

For example but not for limitation, if a sequence A is [0, 7, 1], asequence B that is obtained after sorting is performed on the sequence Ain ascending order is [0, 1, 7]. Therefore, a mapping rule (or, amapping function) p from the sequence A to the sequence B may berepresented as [0, 2, 1]. That is, the first element (with a sequencenumber 0) in the sequence B is the first element (with a sequence number0) in the sequence A; the second element (with a sequence number 1) inthe sequence B is the third element (with a sequence number 2) in thesequence A; and the third element (with a sequence number 2) in thesequence B is the second element (with a sequence number 1) in thesequence A.

Similarly, the mapping function may be obtained according to theforegoing obtained reference sequence and congruential sequence.Therefore, interleaving processing may be performed on the polar codeafter encoding according to the foregoing obtained mapping function.

For example but not for limitation, if the mapping function p is [0, 2,1], a bit value of the first bit (with a sequence number 0) of the polarcode after interleaving is a bit value of the first bit (with a sequencenumber 0) of the polar code before interleaving processing; a bit valueof the second bit (with a sequence number 1) of the polar code afterinterleaving processing is a bit value of the third bit (with a sequencenumber 2) of the polar code before interleaving processing; and a bitvalue of the third bit (with a sequence number 2) of the polar codeafter interleaving processing is a bit value of the second bit (with asequence number 1) of the polar code before interleaving processing.

Optionally, in another embodiment, the control signaling includes but isnot limited to one of the following control channels: a physicaldownlink control channel PDCCH, a physical broadcast channel PBCH, or aphysical uplink control channel PUCCH. It should be understood that, thecontrol signaling may also be referred to as a control channel.

Optionally, in another embodiment, when N=128, the mapping function is:

-   -   {0, 112, 35, 14, 48, 1, 99, 54, 28, 120, 126, 46, 114, 110, 43,        32, 81, 18, 113, 63, 75, 38, 64, 7, 15, 37, 19, 70, 27, 12, 34,        50, 17, 86, 3, 68, 98, 23, 111, 62, 57, 61, 89, 59, 13, 56, 66,        107, 47, 41, 124, 30, 2, 49, 44, 88, 65, 45, 123, 104, 10, 85,        102, 103, 122, 91, 121, 58, 73, 60, 26, 8, 55, 105, 94, 82, 115,        69, 74, 83, 106, 95, 9, 108, 53, 90, 29, 11, 36, 42, 87, 39,        101, 76, 4, 67, 93, 31, 97, 119, 100, 72, 6, 5, 22, 118, 25,        117, 125, 92, 80, 77, 21, 79, 116, 33, 20, 71, 52, 109, 84, 51,        96, 24, 40, 78, 16, 127}.

In this case, the congruential sequence is:

-   -   {4831, 81195000, 985810000, 707190000, 1586500000, 1714800000,        1700400000, 585280000, 1278700000, 1462300000, 1076700000,        1500100000, 645300000, 845220000, 38367000, 586604271,        2108042967, 692938163, 407887860, 603461796, 1964624238,        1878495441, 1715782340, 743376464, 2015855849, 1787239071,        1273295708, 606422001, 177182145, 1487976273, 970150996,        1631941748, 383819152, 1955095723, 646533714, 24877378,        1502264528, 594684317, 470422681, 1506694960, 2042510943,        955321706, 1504167770, 370217906, 992220783, 1044180926,        312459998, 917669471, 43246343, 991814115, 651762791,        2010628637, 1980316514, 1478089592, 160944248, 1308064563,        851016002, 784856594, 1240215484, 825361806, 1258997469,        814087592, 751843707, 443404601, 532873917, 1005115029,        861925101, 1597973492, 709990662, 1393913502, 605122991,        1967041192, 1698052026, 1250215999, 1400292945, 450239142,        1584371213, 1877237738, 2052404489, 1879908509, 1842896099,        398095212, 1374667679, 1410606527, 1991920056, 1077808109,        696325518, 1504588523, 999362636, 818220065, 1486840714,        1212163706, 1805531300, 1620626990, 1342726029, 1438206727,        2012013704, 1636817466, 725632992, 154065231, 1656542782,        1536537366, 1092655187, 1123062412, 1076185001, 1334036773,        1426769131, 906382315, 1466060034, 1991109407, 338132248,        746962174, 3858056, 417837782, 328076384, 1389264039,        1918493289, 1797232165, 1723502100, 1640363964, 202082762,        1233335027, 1149637945, 1054569556, 967989001, 1802513782,        297325845, 2108513993}.

Optionally, in another embodiment, when N=256, the mapping function is:

-   -   {0, 188, 112, 128, 183, 35, 150, 14, 48, 149, 148, 154, 130, 1,        229, 152, 131, 197, 182, 248, 253, 99, 54, 245, 231, 165, 28,        226, 120, 132, 136, 185, 168, 196, 187, 200, 159, 211, 147, 126,        46, 157, 114, 110, 210, 43, 32, 81, 18, 113, 63, 158, 75, 222,        38, 170, 219, 208, 237, 220, 252, 64, 137, 230, 216, 133, 7,        192, 218, 15, 37, 217, 19, 70, 27, 173, 155, 12, 34, 239, 50,        207, 175, 169, 223, 242, 240, 17, 161, 86, 3, 68, 98, 23, 145,        111, 62, 189, 202, 57, 61, 89, 59, 13, 56, 66, 199, 167, 214,        179, 215, 221, 107, 47, 41, 124, 234, 30, 2, 49, 44, 88, 201,        65, 195, 205, 45, 123, 104, 10, 85, 193, 102, 177, 103, 122,        225, 241, 181, 227, 91, 172, 121, 58, 142, 174, 73, 134, 60,        250, 180, 26, 8, 55, 236, 105, 94, 235, 194, 82, 162, 160, 243,        115, 69, 74, 83, 106, 191, 95, 232, 9, 108, 206, 53, 212, 209,        90, 29, 11, 139, 36, 42, 87, 39, 178, 101, 144, 151, 138, 247,        76, 4, 238, 143, 67, 146, 93, 254, 31, 198, 97, 119, 100, 171,        163, 204, 72, 6, 5, 22, 118, 190, 233, 141, 213, 25, 117, 125,        92, 246, 153, 80, 186, 135, 77, 251, 21, 79, 249, 116, 203, 164,        129, 33, 20, 71, 184, 52, 244, 109, 84, 51, 96, 24, 255, 40,        224, 176, 78, 140, 228, 16, 127, 166, 156}.

In this case, the congruential sequence is:

-   -   {4831, 81194617, 985812074, 707191113, 1586533693, 1714817099,        1700440153, 585277195, 1278713105, 1462300206, 1076705974,        1500095396, 645304792, 845221794, 38366853, 586604271,        2108042967, 692938163, 407887860, 603461796, 1964624238,        1878495441, 1715782340, 743376464, 2015855849, 1787239071,        1273295708, 606422001, 177182145, 1487976273, 970150996,        1631941748, 383819152, 1955095723, 646533714, 24877378,        1502264528, 594684317, 470422681, 1506694960, 2042510943,        955321706, 1504167770, 370217906, 992220783, 1044180926,        312459998, 917669471, 43246343, 991814115, 651762791,        2010628637, 1980316514, 1478089592, 160944248, 1308064563,        851016002, 784856594, 1240215484, 825361806, 1258997469,        814087592, 751843707, 443404601, 532873917, 1005115029,        861925101, 1597973492, 709990662, 1393913502, 605122991,        1967041192, 1698052026, 1250215999, 1400292945, 450239142,        1584371213, 1877237738, 2052404489, 1879908509, 1842896099,        398095212, 1374667679, 1410606527, 1991920056, 1077808109,        696325518, 1504588523, 999362636, 818220065, 1486840714,        1212163706, 1805531300, 1620626990, 1342726029, 1438206727,        2012013704, 1636817466, 725632992, 154065231, 1656542782,        1536537366, 1092655187, 1123062412, 1076185001, 1334036773,        1426769131, 906382315, 1466060034, 1991109407, 338132248,        746962174, 3858056, 417837782, 328076384, 1389264039,        1918493289, 1797232165, 1723502100, 1640363964, 202082762,        1233335027, 1149637945, 1054569556, 967989001, 1802513782,        297325845, 2108513993, 19537557, 1950206155, 71942924,        111430407, 205110265, 576970420, 1253182735, 1870101016,        217118420, 534568687, 1571827008, 1500181709, 2095967383,        1749544340, 1245627656, 1593423436, 1546610762, 745013646,        1614686312, 281998645, 54817586, 48683339, 29609066, 1570849805,        108716417, 1835720569, 58046734, 633882600, 2145969080,        314476195, 444154098, 244768114, 1386507993, 694784754,        1378771739, 1668066243, 1937818163, 172875139, 2114570429,        878326000, 222492522, 662787827, 477331400, 1657418255,        1218226548, 624501738, 1248127677, 661603443, 2046225982,        1116956416, 1531925285, 886821112, 1265919204, 1183570799,        133396632, 24266556, 1973597409, 219241501, 1857452702,        237786075, 3495458, 766104137, 1747766794, 1435183092,        585904140, 1078359485, 1373367362, 1031015178, 226549003,        120587290, 1633503909, 869255315, 242828664, 1002426548,        773781521, 1932540862, 1671590406, 1038883588, 1474413406,        652311909, 502236628, 1480274086, 368512907, 253590001,        1479591159, 1775460700, 882709835, 887163369, 575781662,        601079852, 585997076, 492851190, 505523851, 894056225,        459895516, 670291859, 2043545698, 1166579815, 181253595,        1197359719, 2103024843, 105190328, 554801215, 170025231,        1460806907, 1748633445, 968600920, 1349618180, 1310471646,        504670690, 1587364827, 651300708, 686850597, 1173381154,        674724877, 1387351579, 1988032774, 168768945, 1821244575,        1573151334, 135808674, 1908750804, 1264043942, 1878297070,        529244590, 136558256, 1622073596, 2033512954}.

Optionally, in another embodiment, a=7⁵, c=0, and m=2³¹−1.

FIG. 9 is a schematic block diagram of a polar code rate matchingapparatus according to an embodiment of the present invention. The ratematching apparatus 900 in FIG. 9 includes an obtaining unit 901, asorting unit 902, a determining unit 903, and an interleaving unit 904.

The obtaining unit 901 is configured to obtain a congruential sequenceaccording to a length of coded bits of a polar code of a controlsignaling.

The sorting unit 902 is configured to perform sorting processing on thecongruential sequence according to a preset rule, to obtain a referencesequence.

The determining unit 903 is configured to determine a mapping functionaccording to the congruential sequence and the reference sequence.

The interleaving unit 904 is configured to interleave the coded bits ofthe polar code of the control signaling according to the mappingfunction, to generate coded bits after interleaving.

According to the polar code rate matching apparatus in this embodimentof the present invention, a congruential sequence is determined based ona length of coded bits of a polar code of a control signaling; and thecoded bits of the polar code of the control signaling are interleavedusing the congruential sequence, so that a bit sequence structure afterinterleaving can be more even, a frame error rate can be lowered, andcommunication reliability can be improved; and the apparatus isapplicable to a rate matching process for polar codes with differentcode lengths, and has good universality and applicability.

Optionally, in an embodiment, the control signaling is a broadcastsignaling, and the rate matching apparatus further includes a capturingunit 905. The capturing unit 905 is configured to:

-   -   input, according to a preset value E, the first E bits of the        coded bits after interleaving into a cyclic buffer; or    -   perform order-reversing processing on the coded bits after        interleaving; and input, according to a preset value E, the        first E bits of the coded bits after order-reversing processing        into a cyclic buffer.

Optionally, in another embodiment, the obtaining unit 901 is configuredto:

-   -   determine the congruential sequence according to the following        formula:

x(0)=x₀;

and

x(n+1)=[a*x(n)+c]mod m,

where

n=0,1, . . . , (N−2),

-   -   where N is the length of the coded bits of the polar code of the        control signaling, x₀, a, c, and m are particular parameters,        and x(0), x(1), . . . x(N−1) is the congruential sequence. It        should be understood that, that N is the length of the coded        bits of the polar code of the control signaling means that N is        a code length of the polar code.

It is assumed that Q is a given positive integer. If two integers A andB are divided by Q, and obtained remainders are the same, A and B arecongruential to the modulus Q. Formula (2) represents a linearcongruential method, m represents a modulus, and m>0; a represents amultiplier; c represents an increment; and x(0) represents an initialvalue.

Therefore, the mapping function may be determined according to theforegoing obtained congruential sequence and reference sequence. Sortingprocessing is performed on elements in the congruential sequence;therefore, the foregoing mapping function may be determined according topositions of the elements in the congruential sequence and the referencesequence.

For example but not for limitation, if a sequence A is [0, 7, 1], asequence B that is obtained after sorting is performed on the sequence Ain ascending order is [0, 1, 7]. Therefore, a mapping rule (or, amapping function) p from the sequence A to the sequence B may berepresented as [0, 2, 1]. That is, the first element (with a sequencenumber 0) in the sequence B is the first element (with a sequence number0) in the sequence A; the second element (with a sequence number 1) inthe sequence B is the third element (with a sequence number 2) in thesequence A; and the third element (with a sequence number 2) in thesequence B is the second element (with a sequence number 1) in thesequence A.

Similarly, the mapping function may be obtained according to theforegoing obtained reference sequence and congruential sequence.Therefore, interleaving processing may be performed on the polar codeafter encoding according to the foregoing obtained mapping function.

For example but not for limitation, if the mapping function p is [0, 2,1], a bit value of the first bit (with a sequence number 0) of the polarcode after interleaving is a bit value of the first bit (with a sequencenumber 0) of the polar code before interleaving processing; a bit valueof the second bit (with a sequence number 1) of the polar code afterinterleaving processing is a bit value of the third bit (with a sequencenumber 2) of the polar code before interleaving processing; and a bitvalue of the third bit (with a sequence number 2) of the polar codeafter interleaving processing is a bit value of the second bit (with asequence number 1) of the polar code before interleaving processing.

Optionally, in another embodiment, a=7⁵, c=0, and m=2³¹−1.

Optionally, in another embodiment, the control signaling includes but isnot limited to one of the following control channels: a physicaldownlink control channel PDCCH, a physical broadcast channel PBCH, or aphysical uplink control channel PUCCH. It should be understood that, thecontrol signaling may also be referred to as a control channel.

Optionally, in another embodiment, when N=128, the mapping function is:

-   -   {0, 112, 35, 14, 48, 1, 99, 54, 28, 120, 126, 46, 114, 110, 43,        32, 81, 18, 113, 63, 75, 38, 64, 7, 15, 37, 19, 70, 27, 12, 34,        50, 17, 86, 3, 68, 98, 23, 111, 62, 57, 61, 89, 59, 13, 56, 66,        107, 47, 41, 124, 30, 2, 49, 44, 88, 65, 45, 123, 104, 10, 85,        102, 103, 122, 91, 121, 58, 73, 60, 26, 8, 55, 105, 94, 82, 115,        69, 74, 83, 106, 95, 9, 108, 53, 90, 29, 11, 36, 42, 87, 39,        101, 76, 4, 67, 93, 31, 97, 119, 100, 72, 6, 5, 22, 118, 25,        117, 125, 92, 80, 77, 21, 79, 116, 33, 20, 71, 52, 109, 84, 51,        96, 24, 40, 78, 16, 127}.

In this case, the congruential sequence is:

-   -   {4831, 81195000, 985810000, 707190000, 1586500000, 1714800000,        1700400000, 585280000, 1278700000, 1462300000, 1076700000,        1500100000, 645300000, 845220000, 38367000, 586604271,        2108042967, 692938163, 407887860, 603461796, 1964624238,        1878495441, 1715782340, 743376464, 2015855849, 1787239071,        1273295708, 606422001, 177182145, 1487976273, 970150996,        1631941748, 383819152, 1955095723, 646533714, 24877378,        1502264528, 594684317, 470422681, 1506694960, 2042510943,        955321706, 1504167770, 370217906, 992220783, 1044180926,        312459998, 917669471, 43246343, 991814115, 651762791,        2010628637, 1980316514, 1478089592, 160944248, 1308064563,        851016002, 784856594, 1240215484, 825361806, 1258997469,        814087592, 751843707, 443404601, 532873917, 1005115029,        861925101, 1597973492, 709990662, 1393913502, 605122991,        1967041192, 1698052026, 1250215999, 1400292945, 450239142,        1584371213, 1877237738, 2052404489, 1879908509, 1842896099,        398095212, 1374667679, 1410606527, 1991920056, 1077808109,        696325518, 1504588523, 999362636, 818220065, 1486840714,        1212163706, 1805531300, 1620626990, 1342726029, 1438206727,        2012013704, 1636817466, 725632992, 154065231, 1656542782,        1536537366, 1092655187, 1123062412, 1076185001, 1334036773,        1426769131, 906382315, 1466060034, 1991109407, 338132248,        746962174, 3858056, 417837782, 328076384, 1389264039,        1918493289, 1797232165, 1723502100, 1640363964, 202082762,        1233335027, 1149637945, 1054569556, 967989001, 1802513782,        297325845, 2108513993}.

Optionally, in another embodiment, when N=256, the mapping function is:

-   -   {0, 188, 112, 128, 183, 35, 150, 14, 48, 149, 148, 154, 130, 1,        229, 152, 131, 197, 182, 248, 253, 99, 54, 245, 231, 165, 28,        226, 120, 132, 136, 185, 168, 196, 187, 200, 159, 211, 147, 126,        46, 157, 114, 110, 210, 43, 32, 81, 18, 113, 63, 158, 75, 222,        38, 170, 219, 208, 237, 220, 252, 64, 137, 230, 216, 133, 7,        192, 218, 15, 37, 217, 19, 70, 27, 173, 155, 12, 34, 239, 50,        207, 175, 169, 223, 242, 240, 17, 161, 86, 3, 68, 98, 23, 145,        111, 62, 189, 202, 57, 61, 89, 59, 13, 56, 66, 199, 167, 214,        179, 215, 221, 107, 47, 41, 124, 234, 30, 2, 49, 44, 88, 201,        65, 195, 205, 45, 123, 104, 10, 85, 193, 102, 177, 103, 122,        225, 241, 181, 227, 91, 172, 121, 58, 142, 174, 73, 134, 60,        250, 180, 26, 8, 55, 236, 105, 94, 235, 194, 82, 162, 160, 243,        115, 69, 74, 83, 106, 191, 95, 232, 9, 108, 206, 53, 212, 209,        90, 29, 11, 139, 36, 42, 87, 39, 178, 101, 144, 151, 138, 247,        76, 4, 238, 143, 67, 146, 93, 254, 31, 198, 97, 119, 100, 171,        163, 204, 72, 6, 5, 22, 118, 190, 233, 141, 213, 25, 117, 125,        92, 246, 153, 80, 186, 135, 77, 251, 21, 79, 249, 116, 203, 164,        129, 33, 20, 71, 184, 52, 244, 109, 84, 51, 96, 24, 255, 40,        224, 176, 78, 140, 228, 16, 127, 166, 156}.

In this case, the congruential sequence is:

-   -   {4831, 81194617, 985812074, 707191113, 1586533693, 1714817099,        1700440153, 585277195, 1278713105, 1462300206, 1076705974,        1500095396, 645304792, 845221794, 38366853, 586604271,        2108042967, 692938163, 407887860, 603461796, 1964624238,        1878495441, 1715782340, 743376464, 2015855849, 1787239071,        1273295708, 606422001, 177182145, 1487976273, 970150996,        1631941748, 383819152, 1955095723, 646533714, 24877378,        1502264528, 594684317, 470422681, 1506694960, 2042510943,        955321706, 1504167770, 370217906, 992220783, 1044180926,        312459998, 917669471, 43246343, 991814115, 651762791,        2010628637, 1980316514, 1478089592, 160944248, 1308064563,        851016002, 784856594, 1240215484, 825361806, 1258997469,        814087592, 751843707, 443404601, 532873917, 1005115029,        861925101, 1597973492, 709990662, 1393913502, 605122991,        1967041192, 1698052026, 1250215999, 1400292945, 450239142,        1584371213, 1877237738, 2052404489, 1879908509, 1842896099,        398095212, 1374667679, 1410606527, 1991920056, 1077808109,        696325518, 1504588523, 999362636, 818220065, 1486840714,        1212163706, 1805531300, 1620626990, 1342726029, 1438206727,        2012013704, 1636817466, 725632992, 154065231, 1656542782,        1536537366, 1092655187, 1123062412, 1076185001, 1334036773,        1426769131, 906382315, 1466060034, 1991109407, 338132248,        746962174, 3858056, 417837782, 328076384, 1389264039,        1918493289, 1797232165, 1723502100, 1640363964, 202082762,        1233335027, 1149637945, 1054569556, 967989001, 1802513782,        297325845, 2108513993, 19537557, 1950206155, 71942924,        111430407, 205110265, 576970420, 1253182735, 1870101016,        217118420, 534568687, 1571827008, 1500181709, 2095967383,        1749544340, 1245627656, 1593423436, 1546610762, 745013646,        1614686312, 281998645, 54817586, 48683339, 29609066, 1570849805,        108716417, 1835720569, 58046734, 633882600, 2145969080,        314476195, 444154098, 244768114, 1386507993, 694784754,        1378771739, 1668066243, 1937818163, 172875139, 2114570429,        878326000, 222492522, 662787827, 477331400, 1657418255,        1218226548, 624501738, 1248127677, 661603443, 2046225982,        1116956416, 1531925285, 886821112, 1265919204, 1183570799,        133396632, 24266556, 1973597409, 219241501, 1857452702,        237786075, 3495458, 766104137, 1747766794, 1435183092,        585904140, 1078359485, 1373367362, 1031015178, 226549003,        120587290, 1633503909, 869255315, 242828664, 1002426548,        773781521, 1932540862, 1671590406, 1038883588, 1474413406,        652311909, 502236628, 1480274086, 368512907, 253590001,        1479591159, 1775460700, 882709835, 887163369, 575781662,        601079852, 585997076, 492851190, 505523851, 894056225,        459895516, 670291859, 2043545698, 1166579815, 181253595,        1197359719, 2103024843, 105190328, 554801215, 170025231,        1460806907, 1748633445, 968600920, 1349618180, 1310471646,        504670690, 1587364827, 651300708, 686850597, 1173381154,        674724877, 1387351579, 1988032774, 168768945, 1821244575,        1573151334, 135808674, 1908750804, 1264043942, 1878297070,        529244590, 136558256, 1622073596, 2033512954}.

It should be understood that sequence numbers of the foregoing processesdo not necessarily mean execution sequences in various embodiments ofthe present invention. The execution sequences of the processes shouldbe determined according to functions and internal logic of theprocesses, and should not be construed as any limitation on theimplementation processes of the embodiments of the present invention.

A person of ordinary skill in the art may be aware that, the units andsteps in the examples described with reference to the embodimentsdisclosed herein may be implemented by electronic hardware, computersoftware, or a combination thereof To clearly describe theinterchangeability between the hardware and the software, the foregoinghas generally described compositions and steps of each example accordingto functions. Whether the functions are performed by hardware orsoftware depends on particular applications and design constraintconditions of the technical solutions. A person skilled in the art mayuse different methods to implement the described functions for eachparticular application, but it should not be considered that theimplementation goes beyond the scope of the present invention.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, reference may bemade to a corresponding process in the foregoing method embodiments, anddetails are not described herein.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented through some interfaces, indirect couplings or communicationconnections between the apparatuses or units, or electrical connections,mechanical connections, or connections in other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. A part or all of the units may be selected according toactual needs to achieve the objectives of the solutions of theembodiments of the present invention.

In addition, functional units in the embodiments of the presentinvention may be integrated into one processing unit, or each of theunits may exist alone physically, or two or more units are integratedinto one unit. The integrated unit may be implemented in a form ofhardware, or may be implemented in a form of a software functional unit.

When the integrated unit is implemented in the form of a softwarefunctional unit and sold or used as an independent product, theintegrated unit may be stored in a computer-readable storage medium.Based on such an understanding, the technical solutions of the presentinvention essentially, or the part contributing to the prior art, or allor a part of the technical solutions may be implemented in the form of asoftware product. The software product is stored in a storage medium andincludes several instructions for instructing a computer device (whichmay be a personal computer, a server, or a network device) to performall or a part of the steps of the methods described in the embodimentsof the present invention. The foregoing storage medium includes: anymedium that can store program code, such as a Universal Serial Bus (USB)flash drive, a removable hard disk, a read-only memory (ROM), a randomaccess memory (RAM), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific embodiments of thepresent invention, but are not intended to limit the protection scope ofthe present invention. Any modification or replacement readily figuredout by a person skilled in the art within the technical scope disclosedin the present invention shall fall within the protection scope of thepresent invention. Therefore, the protection scope of the presentinvention shall be subject to the protection scope of the claims.Additionally, statements made herein characterizing the invention referto an embodiment of the invention and not necessarily all embodiments.

1. A polar code encoding method, comprising: mapping, by a polar codeencoding apparatus, M bits of a broadcast signaling to M low-reliabilityinformation bits in K information bits of a polar code respectively, andmapping remaining bits of the broadcast signaling to remaininginformation bits of the K information bits, to obtain K bits aftermapping, wherein M<K, and both M and K are positive integers; andperforming, by the polar code encoding apparatus, polar code encoding onthe K bits after mapping, to obtain coded bits after encoding.
 2. Themethod according to claim 1, wherein the M low-reliability informationbits have reliability lower than a threshold, or the M low-reliabilityinformation bits have the lowest reliability out of the K informationbits.
 3. The method according to claim 1, wherein before mapping the Mbits of the broadcast signaling respectively to the M low-reliabilityinformation bits in the K information bits of the polar code, the methodfurther comprises: sorting the K information bits according toreliability of the K information bits.
 4. The method according to claim3, wherein the reliability of one of the K information bits isdetermined according to a bit capacity, a Bhattacharyya parameter, or anerror probability.
 5. The method according to claim 1, wherein afterperforming polar code encoding on the K bits after mapping, the methodfurther comprises: performing sorted congruential interleaving on thecoded bits after encoding, to obtain coded bits after interleaving; andinputting, according to a value E, the first E bits of the coded bitsafter interleaving into a cyclic buffer; or performing order-reversingprocessing on the coded bits after interleaving, and inputting,according to a value E, the first E bits of the coded bits afterorder-reversing processing into a cyclic buffer.
 6. The method accordingto claim 5, wherein performing sorted congruential interleavingcomprises: obtaining a congruential sequence according to a length ofthe coded bits after encoding; performing sorting processing on thecongruential sequence according to a rule, to obtain a referencesequence; determining a mapping function according to the congruentialsequence and the reference sequence; and interleaving the coded bitsafter encoding according to the mapping function, to obtain the codedbits after interleaving.
 7. The method according to claim 6, whereinobtaining the congruential sequence according to the length of the codedbits after encoding comprises: determining the congruential sequenceaccording to the following formula:x(0)=x ₀;andx(n+1)=[a*x(n)+c]mod m,whereinn=0,1, . . . , (N−2), wherein N is the length of the coded bits of thepolar code after encoding, m represents a modulus m>0, a represents amultiplier, c represents an increment, x(0) represents an initial value,and x(0), x(1), . . . , x(N−1) is the congruential sequence.
 8. Themethod according to claim 1, wherein the M bits of the broadcastsignaling are reserved bits.
 9. A polar code rate matching method,comprising: obtaining, by a polar code rate matching apparatus, acongruential sequence according to a length of coded bits of a polarcode of a control signaling; performing, by the polar code rate matchingapparatus, sorting processing on the congruential sequence to obtain areference sequence; determining, by the polar code rate matchingapparatus, a mapping function according to the congruential sequence andthe reference sequence; and interleaving, by the polar code ratematching apparatus, the coded bits of the polar code of the controlsignaling according to the mapping function to generate coded bits afterinterleaving.
 10. The method according to claim 8, wherein the controlsignaling is a broadcast signaling, and the method further comprises:inputting, according to a value E, the first E bits of the coded bitsafter interleaving into a cyclic buffer; or performing order-reversingprocessing on the coded bits after interleaving, and inputting,according to a value E, the first E bits of the coded bits afterorder-reversing processing into a cyclic buffer.
 11. The methodaccording to claim 9, wherein obtaining the congruential sequencecomprises: determining the congruential sequence according to thefollowing formula:x(0)=x ₀;andx(n+1)=[a*x(n)+c]mod m,whereinn=0,1, . . . , (N−2), wherein N is the length of the coded bits of thepolar code of the control signaling, in represents a modulus, m>0, arepresents a multiplier, c represents an increment, x(0) represents aninitial value, and x(0), x(1), . . . , x(N−1) is the congruentialsequence.
 12. The method according to claim 11, wherein a=7 ⁵, c=0, andm=2 ³¹−1.
 13. A polar code encoding apparatus, comprising: a memorycomprising processor-executable instructions stored thereon; and aprocessor coupled to the memory, wherein the processor is configured toexecute the processor-executable instructions to facilitate: mapping Mbits of a broadcast signaling to M low-reliability information bits in Kinformation bits of a polar code respectively, and mapping remainingbits of the broadcast signaling to remaining information bits of the Kinformation bits, to obtain K bits after mapping, wherein M<K, and bothM and K are positive integers; and performing a polar code encoding onthe K bits after mapping, to obtain coded bits after encoding.
 14. Theapparatus according to claim 13, wherein the M low-reliabilityinformation bits have reliability lower than a threshold, or the Mlow-reliability information bits with have the lowest reliability out ofthe K information bits.
 15. The apparatus according to claim 14, whereinthe processor is further configured to execute the processor-executableinstructions to facilitate: sorting the K information bits according toreliability of the K information bits.
 16. The apparatus according toclaim 13, wherein the reliability of one of the K information bits isdetermined according to a bit capacity, a Bhattacharyya parameter, or anerror probability.
 17. The apparatus according to claim 13, wherein theprocessor is further configured to execute the processor-executableinstructions to facilitate: performing sorted congruential interleavingon the coded bits after encoding, to obtain coded bits afterinterleaving; and inputting, according to a value E, the first E bits ofthe coded bits after interleaving into a cyclic buffer; or performingorder-reversing processing on the coded bits after interleaving, andinputting, according to a value E, the first E bits of the coded bitsafter order-reversing processing into a cyclic buffer.
 18. The apparatusaccording to claim 17, wherein performing sorted congruentialinterleaving further comprises: obtaining a congruential sequenceaccording to a length of the coded bits after encoding; performingsorting processing on the congruential sequence according to a rule, toobtain a reference sequence; determining a mapping function according tothe congruential sequence and the reference sequence; and interleavingthe coded bits after encoding according to the mapping function, toobtain the coded bits after interleaving.
 19. The encoding apparatusaccording to claim 18, wherein obtaining the congruential sequenceaccording to the length of the coded bits after encoding is according tothe following formula:x(0)=x ₀;andx(n+1)=[a*x(n)+c]mod m,whereinn=0,1, . . . , (N−2), wherein N is the length of the coded bits of thepolar code after encoding, m represents a modulus, m>0, a represents amultiplier, c represents an increment, x(0) represents an initialvalue), and x(0), x(1), . . . , x(N−1) is the congruential sequence. 20.The encoding apparatus according to claim 13, wherein the M bits of thebroadcast signaling are reserved bits.
 21. A polar code rate matchingapparatus, comprising: a memory comprising processor-executableinstructions stored thereon; and a processor coupled to the memory,wherein the processor is configured to execute the processor-executableinstructions to facilitate: obtaining a congruential sequence accordingto a length of coded bits of a polar code of a control signaling;performing a sorting processing on the congruential sequence accordingto a rule, to obtain a reference sequence; determining a mappingfunction according to the congruential sequence and the referencesequence; and interleaving the coded bits of the polar code of thecontrol signaling according to the mapping function, to generate codedbits after interleaving.
 22. The rate matching apparatus according toclaim 21, wherein the control signaling is a broadcast signaling, andthe processor is further configured to execute the processor-executableinstructions to facilitate: inputting, according to a value E, the firstE bits of the coded bits after interleaving into a cyclic buffer; orperforming order-reversing processing on the coded bits afterinterleaving, and inputting according to a value E, the first E bits ofthe coded bits after order-reversing processing into a cyclic buffer.23. The rate matching apparatus according to claim 21, wherein obtainingthe congruential sequence is according to the following formula:x(0)=x ₀;andx(n+1)=[a*x(n)+c]mod m,whereinn=0,1, . . . , (N−2), wherein N is the length of the coded bits of thepolar code of the control signaling, m represents a modulus, m>0, arepresents a multiplier, c represents an increment, x(0) represents aninitial value, and x(0), x(1), . . . , x(N−1) is the congruentialsequence.
 24. The rate matching apparatus according to claim 23, whereina=7⁵, c=0, and m=2³¹−1.